The field of expansion of tubulars has gained in popularity. In early attempts, a tubular segment was collapsed to get it into a piece of casing and then, when in position; the tubular was expanded to its original dimension. This technique was used for casing patches where the tubular to be expanded was of a fairly short length. One example of this technique is U.S. Pat. No. 5,785,120. Other techniques involved hydraulic pressure applied to a swage to force it through a tubular for expansion. One example of this technique is U.S. Pat. No. 6,029,748. A shortcoming of pressure techniques are that they depend on a solid tubular to avoid losing the driving pressure. For this reason, pressure techniques are not suited for slotted liner or screen expansions. Another pressure technique is illustrated in U.S. Pat. Nos. 6,235,148; 5,348,095 and 6,070,671.
Various expandable well screen products have been developed as illustrated in U.S. Pat. Nos. 6,263,966; 5,901,789 and 6,315,040. Bottom up expansion of a slotted liner using a conical swage is illustrated in U.S. Pat. Nos. 5,667,011 and 5,366,012. Roller devices have been used to provide thrust to a swage as shown in U.S. Pat. No. 5,960,895. Weatherford has advertised roller devices for expansion of tubulars to conform to the shape of the borehole. A problem with such a device, particularly when expanding screen is that some portions of the screen get expanded more than others with structural failures being the result.
What is needed and yet not made available by the prior devices or techniques is a way to expand solid tubing, slotted tubing or screen in a single trip while at the same time taking into consideration the need to not overstress the expanded tubular or screen. Equipment that allows the assembly to be run in the hole together and then selectively allows disengagement after support is established downhole, is also a feature of the present invention. An anchor that can be set and released repeatedly and fit into the expanded tubular or screen is also another aspect of the present invention. Yet another aspect is an anchor that is configured to obtain a sufficient grip for driving the swage but is otherwise limited in its axial travel so as to avoid needless stressing of the tubular of screen after it has already been expanded by about 25% or more. These and other features of the invention will be more readily apparent to a person skilled in the art from a review of the description of the preferred embodiment, which appears below.